#!/usr/bin/python
#
# HD44780 20x4 LCD Test Script for
# Raspberry Pi
#
# Author : Patrick Gramsl
# Site   : http://gramsl.eu

# The wiring for the LCD is as follows:
# 1 : GND
# 2 : 5V
# 3 : Contrast (0-5V)*
# 4 : RS (Register Select)
# 5 : R/W (Read Write)       - GROUND THIS PIN
# 6 : Enable or Strobe
# 7 : Data Bit 0             - NOT USED
# 8 : Data Bit 1             - NOT USED
# 9 : Data Bit 2             - NOT USED
# 10: Data Bit 3             - NOT USED
# 11: Data Bit 4
# 12: Data Bit 5
# 13: Data Bit 6
# 14: Data Bit 7
# 15: LCD Backlight +5V**
# 16: LCD Backlight GND

#import
import RPi.GPIO as GPIO
import time
from datetime import datetime
import os
import glob
import Adafruit_DHT

# Define GPIO to LCD mapping
LCD_RS = 7
LCD_E  = 8
LCD_D4 = 25 
LCD_D5 = 24
LCD_D6 = 23
LCD_D7 = 18
LED_ON = 15

# Define some device constants
LCD_WIDTH = 20    # Maximum characters per line
LCD_CHR = True
LCD_CMD = False

LCD_LINE_1 = 0x80 # LCD RAM address for the 1st line
LCD_LINE_2 = 0xC0 # LCD RAM address for the 2nd line
LCD_LINE_3 = 0x94 # LCD RAM address for the 3rd line
LCD_LINE_4 = 0xD4 # LCD RAM address for the 4th line 

# Timing constants
E_PULSE = 0.00005
E_DELAY = 0.00005

#Set the current Date
date = datetime.now().strftime('%b %d  %H:%M:%S')

#Define the degree symbol
degree = chr(223)

#Set the Sensor type and Pin
sensor = 22
pin = 4

def main():
  # Main program block

  GPIO.setmode(GPIO.BCM)       # Use BCM GPIO numbers
  GPIO.setup(LCD_E, GPIO.OUT)  # E
  GPIO.setup(LCD_RS, GPIO.OUT) # RS
  GPIO.setup(LCD_D4, GPIO.OUT) # DB4
  GPIO.setup(LCD_D5, GPIO.OUT) # DB5
  GPIO.setup(LCD_D6, GPIO.OUT) # DB6
  GPIO.setup(LCD_D7, GPIO.OUT) # DB7
  GPIO.setup(LED_ON, GPIO.OUT) # Backlight enable

  # Initialise display
  lcd_init()
  
  while True:
	lcd_time()
	lcd_temp_hum()
	time.sleep(1)

def lcd_time():
  #redefine the Date and reinitalize every rerun
  getDate = datetime.now().strftime('%b %d %H:%M:%S')
  
  lcd_byte(LCD_LINE_1, LCD_CMD)
  lcd_string("On " + getDate,2)
  
def lcd_temp_hum():
	lcd_temp, lcd_hum = read_hum_temp()
	lcd_out = "{0:0.1f}{1} {2:0.1f}%".format(lcd_temp,degree,lcd_hum)
	lcd_byte(LCD_LINE_4, LCD_CMD)
	lcd_string(lcd_out, 2)
	

def read_hum_temp():
	#read the humidity and temperature from the Sensor using the Adafruit Driver
	humidity, temperature = Adafruit_DHT.read_retry(sensor, pin)

	if humidity is not None and temperature is not None:
		return (temperature, humidity)
	else:
		return "Failed to get reading!"
  
def lcd_init():
  # Initialise display
  lcd_byte(0x33,LCD_CMD)
  lcd_byte(0x32,LCD_CMD)
  lcd_byte(0x28,LCD_CMD)
  lcd_byte(0x0C,LCD_CMD)  
  lcd_byte(0x06,LCD_CMD)
  lcd_byte(0x01,LCD_CMD) 
  
  #Set the intial Lines
  lcd_byte(LCD_LINE_1, LCD_CMD)
  lcd_string("On " + date,2)
  lcd_byte(LCD_LINE_2, LCD_CMD)
  lcd_string("the Temperature",2)  
  lcd_byte(LCD_LINE_3, LCD_CMD)
  lcd_string("and Humidity are:",2)

def lcd_string(message,style):
  # Send string to display
  # style=1 Left justified
  # style=2 Centred
  # style=3 Right justified

  if style==1:
    message = message.ljust(LCD_WIDTH," ")  
  elif style==2:
    message = message.center(LCD_WIDTH," ")
  elif style==3:
    message = message.rjust(LCD_WIDTH," ")

  for i in range(LCD_WIDTH):
    lcd_byte(ord(message[i]),LCD_CHR)

def lcd_byte(bits, mode):
  # Send byte to data pins
  # bits = data
  # mode = True  for character
  #        False for command

  GPIO.output(LCD_RS, mode) # RS

  # High bits
  GPIO.output(LCD_D4, False)
  GPIO.output(LCD_D5, False)
  GPIO.output(LCD_D6, False)
  GPIO.output(LCD_D7, False)
  if bits&0x10==0x10:
    GPIO.output(LCD_D4, True)
  if bits&0x20==0x20:
    GPIO.output(LCD_D5, True)
  if bits&0x40==0x40:
    GPIO.output(LCD_D6, True)
  if bits&0x80==0x80:
    GPIO.output(LCD_D7, True)

  # Toggle 'Enable' pin
  time.sleep(E_DELAY)    
  GPIO.output(LCD_E, True)  
  time.sleep(E_PULSE)
  GPIO.output(LCD_E, False)  
  time.sleep(E_DELAY)      

  # Low bits
  GPIO.output(LCD_D4, False)
  GPIO.output(LCD_D5, False)
  GPIO.output(LCD_D6, False)
  GPIO.output(LCD_D7, False)
  if bits&0x01==0x01:
    GPIO.output(LCD_D4, True)
  if bits&0x02==0x02:
    GPIO.output(LCD_D5, True)
  if bits&0x04==0x04:
    GPIO.output(LCD_D6, True)
  if bits&0x08==0x08:
    GPIO.output(LCD_D7, True)

  # Toggle 'Enable' pin
  time.sleep(E_DELAY)    
  GPIO.output(LCD_E, True)  
  time.sleep(E_PULSE)
  GPIO.output(LCD_E, False)  
  time.sleep(E_DELAY)
	
if __name__ == '__main__':
  main()